Correlation Essays and Research Papers

Instructions for Correlation College Essay Examples

Title: PAPER ON DESCRIPTIVE STATISICS

Total Pages: 3

Words: 1147

Sources:0

Citation Style: APA

Document Type: Essay

Essay Instructions:
focusing on univariate (one variable) descriptive statistics. Now we are going to consider an approach for summarizing the relationship between two variables (bivariate relationships). Correlation analysis and scatterplots (Chapter 7) will be the content for this session and the next session. There are a variety of different correlation coefficients that can be calculated. The one we will focus on in this session is the Pearson Product Moment Correlation Coefficient that is appropriate for describing the nature and strength of a relationship between two quantitative (ordinal, interval or ratio) variables. The nature of the relationship is provided by the sign of the coefficient while the strength of the relationship is provided by the size of the coefficient.

The coefficient can take on a range of values from -1 to +1 (The absence of a sign implies a +). The symbol used for the correlation coefficient is r. An r = 0 indicates there is no relationship between the two variables upon which it is based. An r = 1 or r = -1 indicates a very strong relationship between variables. Use the following as a guide in your analysis. Describe the relationship as weak if r falls between 0.001 and 0.3; the relationship is moderate if r falls between 0.301 and 0.60; describe the relationship as strong if r is greater than 0.60. These interpretations hold true for either + or - coefficients.

In terms of the nature of relationships, there are three basic types-positive relationship, negative relationship, and no relationship. To highlight this, consider the following pairs of variables: number of credits taken last semester and number of books read for enjoyment last semester; number of siblings in family and number of children one hopes to have; and number of credits taken last semester and number of children one hopes to have. The following statements represent each the three types of relationships.

1. As number of credit hours increases, number of books read for enjoyment decreases (negative relationship).

2. As number of siblings increases, number of children hoped for also increases (positive relationship).

3. There is no relationship between number of credit hours and number of children hoped for.

The following generic statements may help:

Positive Correlation

As the values of one variable increase, the values of the other variable tend to increase.

Negative Correlation

As the values of one variable increase, the values of the other tend to decrease.

Zero Correlation

There is no relationship between changes in the values of one variable and changes in the values of the other variable.

Additional details on interpretation of the coefficient are provided in the text.

There is no relationship between changes in the values of one variable and changes in the values of the other variable.

Additional details on interpretation of the coefficient are provided in the text.

One of the concepts that are especially critical for this chapter is that correlation is used to indicate relationship, not causality. A high correlation does not "prove" a causal law of nature. For example, there is a real, positive correlation between the number of gallons of ice cream sold and the number of deaths by drowning. As the number of gallons of ice cream sold increases, so does the number of deaths by drowning. Buying ice cream does not cause a person to drown, but we can safely assume that both activities increase during the hot weather. The point is that correlation indicates a relationship. One of the variables may cause the other, or other variables may affect both. We do not know what the real circumstance is from just the correlation. I have included in Materials a link to a short article (Correlation Not Causation) that addresses this point.

Since Excel provides a very user-friendly process for calculating both correlation coefficients and scatterplots, which are graphs of the bivariate relationship, you do not need to focus on the details of equations that would be used to calculate a coefficient by hand. Instead focus on interpretation and analysis.

Essay Instructions:
Pearson/Spearmen Discussion
Use the homework database (attached) to conduct one Pearson product-moment or Spearman rank-order correlation and interpret the output in layman?s terms ? what do the direction, magnitude, and significance tell you?

“I really do appreciate HelpMyEssay.com. I'm not a good writer and the service really gets me going in the right direction. The staff gets back to me quickly with any concerns that I might have and they are always on time.’’ Tiffany R

“I have had all positive experiences with HelpMyEssay.com. I will recommend your service to everyone I know. Thank you!’’ Charlotte H

“I am finished with school thanks to HelpMyEssay.com. They really did help me graduate college.’’ Bill K